Apparatus for manufacturing diamond cutting tools



R. H. TAYLOR APPARATUS FOR MANUFACTURING DIAMOND CUTTING TOOLS Filed March 29, 1938 3 sheets-Sheet 1 v v v INVENTOR wk 2 WM M,Ww

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APPARATUS FOR MANUFACTURIT'G DIAMOND CUTTING TOQLS Oct. 3, 1939.

Filed March 29, 1958 3 Sheets-Sheet 2 5 R N R E o T N -x W W N QM wQ am H a N% Oct. 3, 1939. R. H. TAYLOR 2,

APPARATUS FOR MANUFACTURING DIAMOND CUTTING TOOLS Filed March 29, 193B 3 Sheets-Sheet 3 ATTORNEYS Patented Oct. 3, 1939 UNITED STATES PATENT OFFICE APPARATUS FOR MANUFACTURING DIAMOND CUTTING TOOLS Rutherford B. Taylor, Millburn, N. 1., assignoi to J. K. Smit & Sons, Inc., New York, N. Y. a corporation of New York Application March 29, 1938, Serial No. 198,716 Claims. (01. 22-65) This invention is directed to an apparatus Mounted on the turntable 2 immediately above which is particularly well adapted for the casting the drive shaft 4 is a block 8, secured to the turnof diamond core bits in which commercial diatable by bolts It. This block 8 may take any monds are set in a metal matrix andfunction as number of forms, but essentially it is provided 5 the cutting medium. centrally with a funnel-shaped cavity l2 extend- 5 One of the objects of my invention is the promg downwardly into the block and then horizonvision of an apparatus for casting diamond tools tally as shown at H. Secured in the side of the whereby a metal matrix of uniform density and block 8 by bolts or set screws i5 is a horizontally free ,of gas voids is assured, the diamonds or extending sleeve Hi, the bore of which is in line '10 cutting stones being securely anchored in this with the horizontally extending portion l4 of the 10 matrix and loosening of these cutting stones funnel I2. 1

when the tool is used avoided. In line with the sleeve (6 and secured thereto In addition to all of the foregoingQmy invenby a split yoke I8 is a removable guide tube 20,

tion provides for protecting the cutting stones the bore of which is in line with the bore of 5 against injury from the molten metal during the' sleeve l6. l8 operation of casting the matrix or body of the The guide tube is for the reception and suptool. port of a bit coupling 22. This bit coupling, it

More specifically the present invention prowill 'be understood, is preformed, is usually of V vides a centrifugal casting machine for the caststeel, and it is to this bit coupling that the core 20 ing of core bits and other diamond tools wherein bit is to be cast.

' provision is made for enveloping the stones in As will be seen from Fig. 1, the extremity of the an inert gas during the casting operation so as guide tube 20 is slightly reduced in diameter to to prevent injury to the skin oft' cutting stones provide clearance as seen at 23, between the wall by the heat of the molten metal -The inertfgas of the bit coupling and the tube, the purpose of is employed not so much as a cooling medium which will be brought out hereinafter. The guide 25 but more by way of a blanket which envelopes tube is also shown tapered to the same angle as the cutting stones during the casting operation to the bore of the bit coupling. This is merely by prevent any reaction between the molten metal way of illustration. The guide tube and the bore and the diamond. I have found in casting core of the bit coupling may be straight.

bits in accordance with this invention that the The bit coupling 22 and guide tube 20 extend 30 cutting stones are unchanged, remaining as into the mold cavity 26 of a mold 24. The bit bright as the original stones, whereas without the coupling is shouldered at 21 and this shoulder use of the inert gas the stones become blackened abuts the mold member as shown at 28. Nut 30 and pitted so that their cutting qualities are serclamps the bit coupling to the mold member, so

iously impaired. that the bit coupling, the guide tube 20 and the 5 In the accompanying drawings, by way of ilmold 24 are securely clamped or secured to each lustration, I have shown an apparatus which is other. m adapted for the practice of my invention: The mold cavity 26 extend through the outer Fig. 1 is a longitudinal sectional elevational face of the mold block 24. This outer face of the 40 view of my improved machine; block is cut back as seen at 3| to provide an annu- 40 Fig. 2 is a plan view of the apparatus of Fig. 1; lar depression for the reception of a removable Fig. 3 is a section on the line 3-3 of Fig. 1; die plate 32, which is provided with ports or Fig. 4 is a section on'the line 4 -4 of Fig. 1; stone-receiving openings 34. The ports 34 extend Fig. 5 is a section on the line 5-5 of Fig. 1; through the die plate as will be seen from Fig. l. Fig. 6 is a fragmentary view to illustrate the The die plate 32 supports an end plate 36, the 45 initial stages of the practice of my invention; adjacent faces of these two plates being depressed Fig. 7 shows in sectional elevation a core bit to provide a chamber 38 between the two plates, as it appears when removed from the machine; this chamber communicating with a port 40 to and which reference will be made in more detail here- Fig. 8 is a similar view of a finished core bit. inafter. I

Referring to the drawings in detail: 2 desig- The die plate 32 and end plate 36 are clamped nates the turntable of my improved machine and in position against the end of the mold member 4 the drive shaft therefor, the turntable being ro- 24 by a clamp plate 42. This clamp plate is contated about a vertical axis and being convenientneoted to the lower part of a block 44 which is 55 ly secured to the drive shaft 4 by a set screw 6. bolted to the turntable 2, this block 44 being prog vided with a V or cradle 46 which receives and supports the mold member 24 as shown, for example, in Fig. 4.

The bottle of the clamp plate 42 is adjustable toward and away from the block 44 by a bolt 48. In the upper end of the plate 42 I provide a clamp screw 68 which bears against a plug 52 projecting from the outer face of the end plate 36. By proper setting of the bolt 46 and setting up of the screw 66 it will be seen that the end plate 36 and die plate 32 can be securely clamped to each other and to the end of the mold memher 2- 1 1 As above pointed out, the mold member 24 is supported in the V or cradle 46 in the block 44. It is held in this position by a yoke 54 which is pivoted at 56 and which is provided with clamping screw 63 contacting the mold member 24, all of which is clearly illustrated in Fig. 4.

Again referring to the die plate 32. This plate, as already pointed out, is provided with stonereceiving openings or ports 34 which are regular in shape, round, for instance, and they receive the irregularly shaped cutting stonesjlL. The disposition of the openings 34 in the die plate 32 depends, of course, upon the desired arrangement of the cutting stones or diamonds in the finished bit.

It will be appreciated, from an inspection of Fig. 1, that when the apparatus is set up the die plate 32 is disposed vertically, and inasmuch as the cutting stones 66 are to be carried on the face of this die plate, it becomes necessary to provide some means for temporarily anchoring the stones in position. To effect this temporary anchorage of the stones in the die plate 32, the same may be sprayed, for example, with any suitable adhesive, as indicated at 62 in Fig. 6, after the cutting stones have bene placed in the openings in the die plate, or I may, for example, place a thin layer of powdered wax over the stones and then heat the wax sufficiently to allow it to flow around the stones so as to anchor the stones'to the plate.

Inasmuch as the openings 34 in the die plate 32 are-of a different shape from the stones which they receive, spaces will be left about the stones 68 between the sides of the stones and the walls of the stone-receiving openings 34. These spaces are not closed by the adhesive 62 and such a construction is deliberately provided in order that an inert gas may be drawn around the sides of the cutting stones and through the openings 34, so that during the casting operation the stones will, in effect, he enveloped in this gas.

This part of my apparatus will now be described. Referrin particularly to Figs. 1, 2, 3 and 5, it will be seen that a non-rotatable plate 64 is provided beneath the turntable 2, and to this plate I secure a block 66 by means of bolts 68. The upper face of this block 66 is provided with annular concentric grooves 10 and I2.

Resting upon the block 66 is a similar'block 14, the underside of the block 14 being provided with concentric grooves 16 and 18 which register at all times with the grooves 18 and '12, respecline 82. This line is connected by a suitable instance, 84, to the port 40 in plug 62 in the outer face of the end plate 86. This port, as above described leads to the chamber 33 between the plate 36 and the die plate 32.

Connected to the annulargroove 12 in the fixed plate 66 is a gas line 86 connected to any suitable source of inert gas such as nitrogen. Leading from the complementary groove or port 18 in the rotatable upper block 14 is a gas line 88 which passes up through the turntable 2 and is connected by a suitable connection 80, such as a metallic hose, for instance, to the top of the funnel-shaped filling cavity I2 in the block 3.

' From an examination of Figs. 1, 2 and 3 it will be seen that a ring 92 is bolted to the top of the block 8, the opening in this ring being in line with the top of the funnel shaped filling opening [2, and that the underside of this ring is provided with an annular grove 34 which communicates with the gas line 96.

Assuming for the moment that suction is drawn on the line 88, it will be apparent that gas will be drawn from the inert gas supply through the line 86, annular ports 12 and I8, gas lines 88 and 90, the annular port 94 in the ring 92 into the filling funnel l2 and from thence through the bores in the sleeve l6 and guide tube 20 to the mold cavity 26, around the cutting stones 60 and through the openings between the sides of the stones and the side walls of the ports 34 in the die 32 and thence to port 40, suction lines 84, 82, annular ports 16 and ID to the suction line' 80.

The blocks 66 and 14 are provided with an oil seal which takes the form of complementary oil grooves 96 in the blocks, these grooves being connected to a source of oil supply 91 through oil conduit 38 connected to each of these grooves by ports I00 with which the block 66 is provided.

In operation, the cutting stones 60 are temporarily anchored in the die plate 32, as above described, and as illustrated in Fig. 6, and then this plate is assembled in the mold as shown in Fig. 1 and clamped in position. The turntable is then rotated about the axis of the drive shaft 4 and suction drawn on the line 80 to draw inert gas through the pouring or charging funnel, etc., about the stones 60 and through the ports 34, as above described, back to the suction device, thereby cleansing the entire mold cavity and enveloping the stones in a blanket of this gas, whereupon with the mold still revolving molten metal is poured into the charging funnel l2 and flows through the tube 20 into the mold cavity 26, and is thrown by centrifugal force against and around the stones 60 so as to embed and part of this gas will be forced out of the mold bit from the mold the casting is machined down to the form shown in Fig. 8. It will be noticed from Fig. '7, which illustrates the rough casting,

that metal filaments or threads I06 project from the working face of the core bit as it is removed Irom the mold. These threads are the metal which escapes from the mold, during casting, past the cutting stones 60, due to these stones being of a shape other than that of the stone-receiving openings 34.

While the construction so far described provides tor the escape of gas from the mold during the casting operation, as above pointed out, further means are provided for eliminating gas or allowing the escape thereof which are shown in Fig. 1, for instance. It will be seen upon an inspection of this figure that the mold block 24 is provided with channels or ports I08 which extend, from the mold cavity rearwardly through the rear face of the block 24. In the casting operation,-therefore, any gas which does not escape vpast the cutting stones can and will be forced out of these leakports 18 to the outside of the mold. The ports are closed by a washer H0, asbestos for instance, which prevents any substantial escape of metal but will permit of the escape of gas, as will be understood.

It is to be understood that changes may be made in the details of construction and arrangement of parts hereinabove described without departing from the spirit and scope of my invention.

What I claim is:

1. Molding apparatus comprising in combination a mold, means for revolving the same about a vertical axis, a die plate for supporting cutting stones in the mold in a vertical plane-lying outside the axis of revolution of the mold, and suction means for drawing inert gas about said stones while pouring molten metal into the mold.

2. Molding apparatus comprising in combination a horizontally disposed mold, a die plate across the end of the mold cavity and supporting cutting stones in a vertical plane, means for revolving the mold about a vertical axis lying outside the plane of the cutting stones, and suction means for drawing an inert gas about the cutting stones while the mold is being revolved and molten metal is being charged thereinto.

3. Molding apparatus comprising in combination a mold, a channeled rotary block, means for revolving said mold and rotating said block simultaneously, a stationary channeled block cooperating with the said rotary block, suction means and an inert gas supply connected to the channels of saidstationary block, a suction line connected to the rotary block and communicating with the cavity of said mold, and a gas line leading from the said rotary block to another part of the mold cavity, whereby as the mold is revolved inert gas from said supply is drawn through the mold cavity.

4. Molding apparatus comprising in combination a mold, a turntable supporting the same, means for rotating the turntable to revolve the mold, a block on said turntable having a filling opening concentric with the axis of rotation of the turntable and communicating with the cavity of said mold, a gas connection communicating with said filling opening, a suction line 'communicating with said mold cavity, a stationary gas supply, a stationary suction means, and rotatable means for maintaining constant communication between the gas supply and suction means, whereby as the mold is revolved gas is drawn through the filling opening of the mold and through the mold cavity to the suction b means.

5. Molding apparatus comprising in combination a .turntable, a mold mounted thereon, its cavity lying outside the axis of rotation of the turntable, a drive shaft attached to said turntable for rotating the same, a channeled block attached to said drive shaft and rotated therewith, a gas line leading from said block to the filling opening of the mold, a suction line leading from said block to the mold cavity, said gas line and suction line revolving with the turntable, a fixed block having channels in constant communication with the channels in the rotatable block, a gas supply connected permanently to one of the channels in the fixed block, and suction means connected permanently to the other channel in the fixed block, whereby gas can be drawn into the filling opening of the mold and through the mold cavity as the mold is revolving.

- RUTHERFORD H. TAYLOR. 

